Tijuana, with a drinking age of 18 and a cluster of 39 bars in a 4-block area catering to young drinkers with prices as low as 0.25 cents a drink, lures crowds of 6,000 to 9,000 people from San Diego across the border on weekend nights. Breath test surveys of those reentering San Diego after a night of drinking in Tijuana, indicate that approximately 30 percent have BACs over .08. It is perhaps the largest consistent concentration of binge drinking in any locale in North America. Three important factors seem to contribute to the magnitude of the problem: (1) Those going to Tijuana have positive expectations about both the social scene, and of the effects of alcohol, (2) they hold beliefs that there are few enforcement risks, and (3) they feel their control over options is limited to Tijuana, since many are under the U.S. legal drinking age, and the prices in the U.S. are a barrier to binge consumption levels. Problematic drinking receives further support from normative pressures within certain specific populations such as military personnel and university students, and by the effect of drinking groups. Recently, concern over the public health problem these impaired youth pose has lead to the creation of the Safe Border Project, a coordinated community effort set to begin July, 1998. It features (1) enhanced enforcement of drinking laws at the border, (2) a center to offer logistical support for detaining highly impaired crossers, and providing transportation home, and (3) a strong media advocacy program. Together these elements should reduce border binge drinking by (a) affecting the risk expectations through media highlighting of risks (i.e., 2 to 3 percent of those crossing back into the U.S. report being robbed or mugged), (b) changing visitor's beliefs about the risk of being arrested for public drunkenness or DUI on the U.S. side of the border, and (c) affecting the perception that Tijuana is a viable option for those seeking outlets for their drinking motivations. We propose to evaluate the effectiveness of the Safe Border Project. Breath-test surveys of those returning north will be the primary dependent variable. These will be related to crash and EMS data. A drinking plan survey of youthful San Diegans entering Tijuana to drink will permit the study of the role of small drinking groups and drinking expectancies on binge drinking. Monthly RDD telephone survey of San Diego County residents 18 to 30 will track the perceptions of cross border drinking by the community from which the target group is drawn. El Paso/Juarez, a border town with a similar border-binge drinking problem will, serve as a comparison site.